It's arbitrary and unfair. You can grimace, you can sweat. You can leap and duckwalk, and you know that if someone would just give you a chance, you could light a Fender Stratocaster on fire and smash it into a wall of 10,000-watt amps. In short, you know you've got everything it takes to be a great rock guitarist, except for one thing. You haven't got the faintest idea how to play guitar. Not only that, you don't even own a guitar.

If that's your problem, relax.

The latest fringe musical fad, air guitar—in which aficionados mime guitar-hero antics to the accompaniment of a favorite LP—allows any nebbish to play like Springsteen, Clapton or Hendrix, blindfolded. A grass-roots art once confined to adolescent bedrooms, air guitaring has lately become the subject of local contests and a new manual, The Complete Air Guitar Handbook (Pocket Books, $2.95) by Mike Moffitt, 35, a Tampa photographer, and John McKenna, 30, a Minneapolis movie marketer who has seen Bruce Springsteen in concert 63 times.

In addition to citing Great Moments in Air Guitar History (Neil Young in The Last Waltz; Joe Cocker, anytime) the guide explains how to tune an air guitar ("with an air piano") and lists equipment (air amps, mirrors) and acceptable guitar substitutes (tennis rackets, yes; chain saws, no). Alas, lack of musical knowledge alone is no guarantee of success; air guitarists, the authors note, need not even have "the brains of a begonia" to succeed.

Flush with the modest success of the Handbook, Moffitt and McKenna are already at work on a second manual, in which they will show readers how to improve their social skills by practicing with pneumatic dolls. Their tentative title: I'm OK, You're Inflatable.